Earthquake Resistance of Beam-Column Connections in Weak-Beam Strong-Column Reinforced Concrete Frames

通过反复荷载作用下的平面试件试验和非线性有限元分析，研究了钢筋混凝土梁柱内节点的剪力传递机理。节点剪力传递机制随粘结劣化沿着梁筋方向发生变化。当沿梁钢筋保持沿着良好粘结时，对角压应力均匀分布在接缝板内。然而，随着粘结性能的恶化，压应力逐渐集中在接头的主对角线上。节点内部的横向钢筋对节点的抗剪承载力没有贡献，而是限制了节点核心混凝土。在试验过程中，尽管有很高的剪切力输入到节点中，但没有观察到节点剪切破坏。在节点中设置横梁，板约束节点核心区，提高节点抗剪能力，提出了考虑弱梁强柱设计结构变形极限的梁柱内节点抗震设计准则。在一定程度上，可以允许沿梁钢筋沿着的粘结劣化，该极限是根据非线性地震反应分析确定的。为了防止梁弯曲屈服后节点发生剪压破坏，节点的剪力输入必须与混凝土的抗压强度成正比。

The shear transfer mechanism of a reinforced concrete interior beamcolumn joint was studied through the laboratory tests of plane specimens under reversed cyclic loading and the nonlinear finite element analysis. The joint shear transfer mechanism changes with bond deterioration along the beam reinforcement. When a good bond is maintained along the beam reinforcement, diagonal compressive stresses distribute uniformly within the joint panel. However, the compressive stresses come to concentrate on the joint main diagonal with the bond deterioration. The transverse reinforcement within the joint does not contribute to the shear resistance, but confines the joint core concrete.Three-dimensional beam-column joints with slabs were tested under the bi-directional loading reversals. The joint shear failure was not observed during the tests despite fo a high shear force input into the joint. The transverse beams framing into the joint and the slabs confined the joint core increasing the joint shear resistance.The earthquake resistant design criteria were proposed for interior beam-column joints taking into account the expected deformation limits of structures designed by the weak-beam strong-column concept. The bond deterioration along the beam reinforcement may be permitted to some extent, the limit which was determined on the basis of the nonlinear earthquake response analyses. The shear force input into the joint must be limited in proportion to the concrete compressive strength in order to prevent the joint shear compression failure after beam flexural yielding.